http-wokou/pkg/client.go

/*
				GNU GENERAL PUBLIC LICENSE
                 Version 3, 29 June 2007

 Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

 http-wokou, An HTTP Proxying framework for bypassing DNS Security
 Copyright (C) 2024 Russell Hrubesky, ChiralWorks Software LLC

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <https://www.gnu.org/licenses/>.

*/

package httpserver

import (
	"fmt"
	"io"
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
)

/*
Retrieve the site audit config file from Semrush

	returns a byte array of the body, the content type of the resp, and an error
*/
func (c *Controller) RetrieveStaticResource(method string, path string, ctx *gin.Context) ([]byte, string, int, error) {
	cacheResp := c.GetResource(path)
	if cacheResp != nil {
		return cacheResp.Data, cacheResp.Ctype, cacheResp.Rcode, nil
	}
	url := fmt.Sprintf("%s%s", c.Config.FullAltAllowedDomain, path)
	req, err := http.NewRequest(method, url, nil)
	if err != nil {
		return nil, "", 500, err
	}
	c.setHeaders(req, ctx)

	resp, err := c.Client.Do(req)
	if err != nil {
		return nil, "", 500, err
	}
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, "", 500, err
	}
	if resp.StatusCode == 200 {
		c.CacheResource(path, NewCachedResource(b, resp.Header.Get("content-type"), resp.StatusCode))
	}
	return c.pageMod(b), resp.Header.Get("content-type"), resp.StatusCode, nil

}

/*
Perform a call against the siteaudit api

	:param path: the URI path with the query
	:param query: the query to add to the request
	:param body: an io.Reader to push into the request body
	:returns a byte array of the response, the content type and an error
*/
func (c *Controller) SiteauditApiCall(method string, path string, query string, body io.Reader, ctx *gin.Context) ([]byte, string, int, error) {

	query = strings.ReplaceAll(query, c.Config.FullProxyDomain, c.Config.FullDomain)
	url := fmt.Sprintf("%s%s?%s", c.Config.FullDomain, path, query)
	req, err := http.NewRequest(method, url, body)
	if err != nil {
		return nil, "", 500, err
	}
	c.setHeaders(req, ctx)
	resp, err := c.Client.Do(req)
	if err != nil {
		return nil, "", 500, err
	}
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, "", 500, err
	}
	return c.pageMod(b), resp.Header.Get("content-type"), resp.StatusCode, nil

}

/*
Generic site call to the semrush site
*/
func (c *Controller) SemrushGeneric(ctx *gin.Context) ([]byte, string, int, error) {
	path := ctx.Param("ProxiedPath")
	method := ctx.Request.Method
	query := ctx.Request.URL.RawQuery
	body := ctx.Request.Body
	var reqUrl string
	if query != "" {
		reqUrl = fmt.Sprintf("%s%s?%s", c.Config.FullDomain, path, query)
	} else {
		reqUrl = fmt.Sprintf("%s%s", c.Config.FullDomain, path)
	}
	cacheResp := c.GetResource(path)

	if cacheResp != nil {
		return cacheResp.Data, cacheResp.Ctype, cacheResp.Rcode, nil
	}

	req, err := http.NewRequest(method, reqUrl, body)
	if err != nil {
		return nil, "", 500, err
	}
	c.setHeaders(req, ctx)
	resp, err := c.Client.Do(req)
	if err != nil {
		return nil, "", 500, err
	}
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, "", 500, err
	}

	for k, v := range resp.Header {
		_, ok := NonmutableHeaders[k]
		if !ok {
			ctx.Header(k, v[0])
		}
	}
	if resp.StatusCode == 200 {
		if query == "" {
			if method == "GET" {
				c.CacheResource(path, NewCachedResource(b, resp.Header.Get("content-type"), resp.StatusCode))
			}
		}
	}

	return c.pageMod(b), resp.Header.Get("content-type"), resp.StatusCode, nil

}

/*
Sets the request headers to whatever is defined in this private method

	:param req: a pointer to an HTTP request
*/
func (c *Controller) setHeaders(req *http.Request, ctx *gin.Context) {

	req.AddCookie(c.Config.PhpSession)
	req.AddCookie(c.Config.SsoToken)
	req.Header.Set("User-Agent", c.Config.UserAgent)
	req.Header.Set("Referer", c.Config.FullDomain)
	req.Header.Set("Origin", c.Config.FullDomain)

	for k, v := range ctx.Request.Header {
		_, ok := NonmutableHeaders[k]
		if !ok {
			req.Header.Add(k, v[0])
		}
	}

}

/*
Rewrite all occurences of these values into the response body
*/
func (c *Controller) pageMod(data []byte) []byte {
	newBody := strings.ReplaceAll(string(data), "\"srf-browser-unhappy\"", "\"srf-browser-unhappy\" style=\"display:none;\"")
	newBody = strings.ReplaceAll(newBody, "\"srf-navbar__right\"", "\"srf-navbar__right\" style=\"display:none;\"")
	newBody = strings.ReplaceAll(newBody, "<footer", "<footer style=\"display:none;\"")
	newBody = strings.ReplaceAll(newBody, "\"srf-report-sidebar-extras\"", "\"srf-report-sidebar-extra\" style=\"display:none;\"")
	newBody = strings.ReplaceAll(newBody, c.Config.AllowedDomain, c.Config.ProxyAddr)
	newBody = strings.ReplaceAll(newBody, c.Config.AltAllowedDomain, c.Config.ProxyAddr)
	return []byte(newBody)

}